Varicella Zoster

History

Fact

Explanation

Papulovesicular rash [6]

Varicella zoster virus (VZV) is a neurotrophic alpha-herpesvirus. [2,6] Which is acquired through the respiratory secretions or direct contact with the vesicles, then the virus spread to regional lymph nodes, giving rise to primary viremic phase where virus disseminate to the liver or other cells of the mononuclear
phagocyte system. This occurs during the incubation period which is usually has a 10-21 days of incubation period. [3] The rash initially appears on the face, chest, and back then spread to the rest of the body, it is itchy and fluid-filled blisters later turn into scabs. Rash also involves the inside of the mouth, eyelids and genital area. After about 1 week, blisters will become scabs.

Fever [6]

Prodrome period of chickenpox lasts about 24 to 48 h before the first skin lesions appear and it consists of fever and other constitutional symptoms. [3] They will have high fever due to the associated inflammation. [2] Reactivation might cause mild fever.

Constitutional symptoms: malaise, anorexia, and lethargy [1]

They can have constitutional symptoms [1] developing 1-2 days before the onset of the rash.

Earache, reduction of hearing

This can occur if the varicella infection is complicated with otitis media. [1]

Features of hepatits [9] : Right upper abdominal pain and vomiting

This is due to hepatitis, which is a benign complication of the varicella. [3]

Shortness of breath and cough due to pneumonia [7]

This occurs if complicated with varicella pneumonitis, which is an uncommon complication of varicella. [1] Develops 1-6 days after the onset of disease.

Skin infections [1]

There can be invasion of the skin lesions by group A β-hemolytic streptococci, leading to cellulitis, which might end up in necrotizing fasciitis on some occasions. Skin infections due to secondary bacterial infections are the most common complication of varicella. [1]

Features of cerebelitis [8] : Vertigo, speech disrurbances

If complicated with cerebellitis they can have features related to cerebellar pathology. [1] Usually associated with reactvation. [8]

Headache, drowsiness, behavioural change [1]

If complicated with encephalitis. [1]

Chest pain [1]

Due to the myocarditis and pericarditis. [1]

Features of arthriti [1] : Joint and bone pain

Due to the osteomyelitis there can be bone pain. Monoarticular pyogenic arthritis may also be a complication of varicella. [1]

Though this is a rare complication of varicella infection, it can result in severe haemorrhage that is rapidly fatal. They can have thrombocytopenia due to reduced production and survival of platelets and transient hypersplenism, [5] which may need intravenous immunoglobulin therapy. Hemorrhagic disease
can lead to disseminated intravascular coagulopathy. Intracranial haemorrhage can develop in these patients. [4]

There can be pneumonia due to varizella pneumonitis, and on some occcasions interstitial pneumonia. [2]

Focal neurological deficits (stroke) [7]

Varicella zoster virus vasculopathy results when the infection involves the large or small cerebral arteries. [2]

Herpes zoster [5,7]

This is a latent infection where primary infection causes varicella (chickenpox),and then virus becomes latent in cranial nerve ganglia, dorsal root ganglia, and autonomic ganglia which can later reactivates and causes a wide range of neurologic disease. Herpes zoster appears along a 1-3 dermatomes and gradually maculopapular rash evolves into vesicles. [2,5] Other features of reactivation includes postherpetic neuralgia, vasculopathy, myelopathy, retinal necrosis and cerebellitis. [2]

Skin bruising, petechiae, purpura and haemorrhagic vessicles [4]

This is due to hemorrhagic varicella, which is a rare but fatal complication of the disease. [4]

Differential Diagnoses

Fact

Explanation

Meningoencephalitis [8]

Altered level of consciousness, seizures, fever, vasomotor instability may be present. Evaluation requires a lumbar puncture. [1] Most of the time cause would be Herpes simplex encephalitis. Meningeal irritation will result in neck stiffness, positive kernig and Brudzinski sign.

This is a common condition in children. Localized red rash where skin may appear red or brown with blisters and pus will be evident, there may be associated lymphadenopathy. A bacterial culture of the skin is the investigation to diagnose the condition. Secondary bacterial infections complicating the varicella [2] may look similar to impetigo.

Acute Nerve Injury [6]

Focal neurologic deficits such as facial nerve palsy, concomitant hemiplegia, paresis of the arm, radiculitis resulting in paresis of the leg, and abducens nerve palsy can be seen in patients with varicella as well. [4]

Investigations - for Diagnosis

Fact

Explanation

Serology [2]

IgG or IgM antibodies to varicella should be checked in acute- and convalescent-phase serum. [6] This lacks a clinical significance as rapid confirmation of infection is necessary for the management. Therefore diagnosis is made primarily on clinical features. IgM antibodies are not used routinely as it lacks the specificity and sensitivity. These tests are valuable in identifying individuals who may benefit from immunization with varicella vaccine. [1]

Immunofluorescence [1]

Polyclonal or monoclonal antibodies to VZV antigens can be used to rapid identification using the epithelial cells from suspected
varicella lesions. [1]

Investigations - Fitness for Management

Fact

Explanation

Full blood count [2]

These patients may be having thrombocytopenia (<30 000/μl), granulocytopenia (<500/μl), neutropenia as haematologic complications. [1] As they present with fever and have a high risk of superinfections with bacteria, it is important to evaluate for other infections. Elevated lymphocytes may be seen in these patients. White cell count may be elevated in bacterial infections (leucocytosis), platelets may become low in dengue fever.

Haemoglobin [2]

They can develop anemia requiring transfusion. [1] Anaemia occurs due to the haemolysis induced by varicella infection.

References

Management - General Measures

Fact

Explanation

Isolation

VZV is a highly infectious disease. Infected individual transmits the disease by direct contact with skin lesions and by respiratory droplets. [1] They can return to their usual work after about 10 days of onset of the rash.

As the rash is itchy, patient tends to scratch the lesions often. Scratching leads to scarring of the skin and high risk of bacterial infections. [1]
Wearing gloves on hands, especially at night, trimming fingernails and using medications to reduce itching:
Hydroxyzine hydrochloride,
Diphenhydramine etc are valuable measures in reducing the itching.

Diet

No restrictions, but a soft, blended diet may be needed if sores are there in the mouth. [2]

Analgesics [5]

Acetaminophen or ibuprofen used for fever. Aspirin should not be used as, the combination can cause Reye's syndrome. [1]

Vaccination [4]

Live Attenuated Varicella vaccines are shown to be safe and effective. [2] Usually 2 doses are required for children aged 12 m–13 yrs and single dose is required for age >13 yrs
Two doses, should be given at 4–8-wk interval. Congenital immunodeficiency, blood dyscrasias, leukemia, lymphoma, other malignancies , symptomatic HIV infection, high-dose systemic corticosteroids, pregnancy are main contraindications for vaccination. [3]

Management - Specific Treatments

Fact

Explanation

Antiviral therapy : Acyclovir [3]

Treatment with intravenous Acyclovir is required in patients who have the evidence of disseminated disease, in newborns who were exposed to VZV shortly after birth and high risk groups such as malignancy, bone marrow or organ transplantation, high-dose steroid therapy, congenital T-cell immunodeficiencies and HIV infection. Dose would be : children < 1 yr, 10 mg/kg/dose given every 8 h as 1h infusion
children > 1 yr, 500 mg/m2/dose given every 8 h as 1-h infusion
Adults, 10 mg/kg/dose given every 8 h as 1-h infusion
for 7 days. [2] But studies have shown that use of acyclovir within 24 hours of illness , reduces the overall severity of the illness. [1]

Varicella-zoster immune globulin [VZIG] [4]

When an immunocompromised person is exposed to an infected patient with chicken pox, they should receive IVIG within 96 hrs of exposure. [1]

Treating complications Eg:- pneumonia, [4], skin infections

Skin infections and pneumonia may be treated with antibiotics. Encephalitis patients should receive antiviral drugs. Hospitalization may be required. [1]